Jeffrey J. McDonnell is a Distinguished Professor of Hydrology at the University of Saskatchewan in Canada. His research focuses on streamflow generation and the use of stable isotopes for tracing the water cycle. He is winner of a number of prizes, including the Horton Medal from the American Geophysical Union (2025), the Ray K. Linsley Award for Surface Water from the American Institute of Hydrology (2023), the International Hydrology Prize from the International Association of Hydrological, UNESCO and the World Meteorological Organization (2016), and the Dalton Medal from the European Geosciences Union (2009). McDonnell is a 2024 Officer of the Order of Canada and a fellow of the Royal Society of Canada, the American Association for the Advancement of Science, Academia Europaea, the American Geophysical Union, and the Geological Society of America. He is the former President of the AGU Hydrology Section.